Adult tricycles have become increasingly popular in recent years, in part because of their more frequent commercial use as in factories. These velocipedes are also a popular form of transportation for persons traveling to and from shopping centers and the like, and for leisure riding.
Various forms of convertible bicycles and tricycles are known in the prior art and/or in the trade. These velocipedes usually have interchangeable rear frames for converting the velocipede between a tricycle, bicycle or tandem bicycle, for example. Almost any such velocipede can be optionally provided with a motor, if desired.
A bicycle comprising separable front and rear frame parts is shown in U.S. Pat. No. 3,359,012, in which a crank hanger tube forms part of a coupling operatively interconnecting the front and rear frame parts. The bottom of this tube has a recess which receives a tab extending upwardly from the bottom of a semi-cylindrical coupling member which embraces the front of the crank hanger tube and is part of the front frame part. The coupling member is integral with a plate-like member which has a hole receiving a threaded stud on the rear frame part, with a nut received on the stud clamping the parts together. In this construction, substantially the entire load of the rear frame member is actually carried by the lower portion of the semi-cylindrical coupling member. If the load is very heavy this portion of the coupling member could be expected to bend since it is supported only along its front portion. The stud and nut could not reasonably be relied upon to carry the load or to clamp tightly enough to be reliable. Other patents known to applicant and of passing interests are U.S. Pat. Nos. 1,584,314, and 3,680,879.